3 households chased. None by the host.

Every reminder is worked backwards from the reply deadline and sent only to the households that have not answered — at a civil hour where they are. A household that replies drops out of every later send automatically.

Step	Who it went to	Reach	Status
Invitation sent	All 8 households		Delivered
First reminder	Those who had not opened		Sent
Reply deadline nears	3 silent households		Sent
Final call	The last few, by hand		Sent
Deadline	Count locked at 18		Closed

Counted against the 108 messages this plan includes — six per guest, and this event used a fraction of them.